Phonograph



Sept. 2, 1941. E. c. GUEDON PHONOGRAPH 2 Sheets-Sheet i Filed July 29,1959 Buvcuto'r mm M SeptQZ, 1941. Y E. c. GUEDON PHONOGRAPH Filed July29; 1939 2 Sheets-Sheet 2 Patented Sept. 2, 1941 TATES .ATENT FFICEPHONOGH Emile C. Guedon, Audubon, N. .i'., assignor to Radio Corporationof America, a corporation of Delaware Application July 29, 1939, SerialNo. 287,292

1 Claim. (Cl. 74-191) graph turntables at the desired speed. This may bedue to a number of causes, such as variations in line voltage, variableloads, etc.

The primary object of my present invention is to provide a phonographturntable drive which can be readily adjusted to provide the desiredspeed.

More particularly, it is an object of my present invention to provide animproved drive for phonograph turntables which can be readily adjustedto provide correct playing speed for the turntable.

Another object of my present invention is to provide an inexpensive,self-starting, motordriven turntable for the playing of phonographrecords.

In accordance with my present invention, I provide a self-starting,electric motor which is pivotally supported on a suitable frame orcradle and which has an approximately vertical drive shaft provided witha conical driving surface. In one form of my invention, I connect afriction wheel to the turntable for rotation therewith and arrange themotor in a manner such that the conical driving surface thereof is inconstant engagement with the periphery of the friction wheel, thefriction between the conical driving surface and the friction wheeleffecting rotation of'the turntable. I also provideadjusting means'forthe frame or cradle of the motor so that the motor can be readilyadjusted to bring different portions of its conical driving surface intoengagement .with the periphery of the friction wheel. In this manner,the speed of the turntable can be readily altered to suit variable loadsand variable voltage conditions.

In accordance with another form of my inand couple the pulley to afriction wheel by means of a belt. The motor, as before, is pivotallymounted and has its conical driving surface in constant engagement withthe friction wheel which, in this modification, is made adjustable alongthe conical driving surface to effect variations in speed. The novelfeatures that I consider characteristic of my invention are set forth.with particularity in the appended claim. The invention objects andadvantages thereof, will best'be understood from the followingdescription of two embodiments thereof, when read in connection with theaccompanyingdrawings, in which Figure 1 is a plan view'of a turntabledriving mechanism embodying one form of my invention,

Figure 2 is a sectional view' thereof taken along the line 11-11 ofFigure 1,

Figure 3 is a plan view of a phonograph drive mechanism showing anotherform of my invention, and

Figure 4 is a side elevation of the latter form of my invention.

Referring more particularly to the drawings, wherein similar referencenumerals designate corresponding parts throughout, I have shown, inFigures 1 and 2, a motorboar'd l which supports a frame 3 in which isrotatably mounted a spindle 5. Fixed to the spindle 5 is a rubber-tireddisk I constituting a friction wheel, the disk I being connected to aturntable 9 by means of a plurality of upstandingpins ll which arereceived in rubber grommets l3 secured to the turntable 9. Thisconstruction may be of the type disclosed, for example, in the U. S.patent to Blessing and Guedon, No. 2,157,158, and serves efiectively toprevent the transmission of vibrations to a record supported on theturntable 9 during playing.

Fixed to the frame 3 are a pair of oppositely disposed brackets l5formed with knife edges or other suitable fulcrums H on which a motorfventlon, I provide a pulley on the turntable shaft itself, however,both as to its-organization and method of operation, together withadditional frame or cradle I9 is pivotally mounted. A suitable electricmotor 2|, preferably of the selfstarting type, and having a drivingshaft 23 provided with a conical driving surface or tip 23a,

is pivotally carried by the cradle or frame IS on a pair of oppositelydisposed pins 25, the shaft 23 being disposed between the fulcrums l1and, the pivot pins 25. The center of gravity of the motor 2l is locatedto the left of the pivotal mountings l1 and 25 (as viewed in Fig. 2) sothat the motor 2| always tends ,to rotate in a counter-clockwisedirection and therefore the conical driving surface 23a will always bemaintained in engagement with the periphery of the friction wheel I.

ical driving surface 23a. and the periphery of the rubber-tired frictionwheel I will effect rotation of the wheel I and theturntable 9. d Toalter the speed of the turntable, an adjusting screw 1 is threaded intothe frame 3 and is brought down into engagement with the cross-arm l9aof the cradle l9. As the screw Z'lis advanced in a downward direction,it will effect clockwise rotation of the cradle l9 and the motor 2iabout the fulcrums or knife edges I1. This raises the conical drivingsurface 23a and at the same time tends to move it away from theperiphery of the friction wheel 1. However, inasmuch as the center ofgravity of the motor 2| is to the left of the pivot'pins 25, it isobvious that the counterclockwise movement of the motor about the pins25 will offset the corresponding clockwise movement of the motorassembly about the fulcrums l1, and the conical driving surface 230 willstill be maintained in engagement with the periphery of the frictionwheel 1, although at a larger diameter. This, of course, will increasethe speed of the turntable. Conversely, if the adjusting screw 21 isretracted in an upward direction, the cross-arm l9 will follow it, andthe motor assembly will pivot around the fulcrums l1 in acounter-clockwise direction to bringa portion of the driving cone 23:;having a smaller diameter into contact with the friction wheel 1 andthereby reduce the speed of the turntable.

In the modification of my invention shown in Figures 3 and 4, theturntable spindle 5 has fixed thereto a pulley 3| which is connected bymeans,

of a belt 33 to a second pulley 35 rotatably mounted on the bottomextension of the adjusting screw 21 and fixed to a rubber-tired frictionwheel 31. An idler pulley 39 carried on a pivotally mounted bracket 4|constantly maintains tension in the belt 33 under the influence of aspring 43.

Pivotally mounted on a bracket 45 is the motor 2| which is constantlybiased in a clockwise direction by a spring 41 to maintain the conicaldriving surface 23a in constant engagement with the friction wheel 31.By merely manipulating the adjusting screw 21 one way or the other, itis obvious that the friction wheel 31 will be moved along the conicaldriving surface 23a to thereby vary the speed imparted to the frictionwheel 31 by the motor and thus to correspondingly vary the speed of thepulley 3| and the turntable mounting.

Although I have shown and'described but two embodiments of my invention,I am fully aware surface, said motor shaft being disposed between thepivotal mounting of said frame and the pivotal mounting of said motor onsaid frame and the center of gravity of said motor being located on thesame side of both of said pivotal mountings whereby said motorconstantly tends to swing about both said mountings in a direction toeffect engagement between said conical driving surface and said frictionwheel, and adjustable means associated with said frame for adjustingsaid frame about said first named means whereby to vary the point ofengagement of said conical surface with said friction wheel to therebyalter the speed imparted to said turntable by said motor.

, FWHLE C. GUEDON.

